1 Welcome Thanks for joining this ITRC Training

1 Welcome – Thanks for joining this ITRC Training Class ITRC Internet-based training and Technical and Regulatory Guidance Integrated DNAPL Site Strategy Sponsored by: Interstate Technology and Regulatory Council (www. itrcweb. org) Hosted by: US EPA Clean Up Information Network (www. cluin. org)

2 Housekeeping u u Course time is 2¼ hours Question & Answer breaks • Phone - unmute *6 to ask • u question out loud Simulcast - ? icon at top to type in a question Turn off any pop-up blockers u u u Move through slides • Arrow icons at top of screen • List of slides on left Feedback form available from last slide – please complete before leaving This event is being recorded Download slides as PPT or PDF Go to slide 1 Move back 1 slide Move forward 1 slide Go to last slide Go to seminar homepage Submit comment or question Report technical problems Copyright 2013 Interstate Technology & Regulatory Council, 50 F Street, NW, Suite 350, Washington, DC 20001

3 ITRC (www. itrcweb. org) – Shaping the Future of Regulatory Acceptance u u Host organization Network • State regulators u Disclaimer • Full version in “Notes” section • Partially funded by the U. S. § All 50 states, PR, DC government • Federal partners § ITRC nor US government warrantee material § ITRC nor US government DOE DOD endorse specific products EPA • ITRC materials copyrighted • ITRC Industry Affiliates Program u Available from www. itrcweb. org • Technical and regulatory guidance documents • Academia • Community stakeholders • Internet-based and classroom training schedule • More…

4 Meet the ITRC Trainers Aaron Cohen Florida Department of Env. Protection Tallahassee, FL 850 -245 -8962 Aaron. cohen@ dep. state. fl. us Dan Bryant Geo-Cleanse International, Inc Matawan, NJ 732 -970 -6696 dbryant@ geocleanse. com Wilson Clayton Trihydro Corporation Evergreen, CO 303 -679 -3143 wclayton@trihydro. com Heather Rectanus Battelle Madison, WI 608 -824 -9191 rectanush@battelle. org Alex Mac. Donald California Water Boards Rancho Cordova, CA 916 -464 -4625 amacdonald@ waterboards. ca. gov Ryan Wymore CDM Denver, CO 720 -264 -1110 wymorera@cdmsmith. com

5 The Problem… Are you tired of throwing money and time at your chlorinated solvent sites with little improvement in return?

6 Are You Dealing with These Common Site Challenges? u Incomplete understanding of DNAPL sites u Complex matrix – manmade and natural u Unrealistic remedial objectives u Selected remedy is not satisfactory Oh, what to do?

7 ITRC IDSS Team u. States • • • u Federal Agencies • NAVFAC • NFESC • AFCEE • EPA • SERDP • DOE u Community Stakeholders • Mtn Area Land Trust u. Universities • Yale • Colorado State u Industry • Tufts Univ. • Arcadis • Yale • Aquifer • U. of New Solutions Mexico • Battelle California Delaware Florida Maine Minnesota Massachusetts Vermont Virginia Utah • Burns and • • • Mc. Donnell Engineering CDM Conestoga. Rovers & Assoc Dajak Fishbeck, Thompson, Carr & Huber Geo-Cleanse Int, Inc. Geosyntec GSI Environmental JRW Bioremediation Kleinfelder Langan Engineering Microseeps • Porewater Solutions, Inc • Reg. Tech • T. H. Wiedemeier Assoc.

8 The Solution is an Integrated DNAPL Site Strategy (IDSS) Comprehensive site management u When can you develop an IDSS? u • Anytime! u Who should use this IDSS? • Experienced practitioners and regulators ITRC Technical and Regulatory Guidance Document: Integrated DNAPL Site Strategy (IDSS-1, 2011)

9 An Integrated DNAPL Site Strategy u Conceptual site model • Chapter 2 u Remedial objectives • Chapter 3 u Remedial approach • Chapter 4 u Monitoring approach • Chapter 5 u Evaluating your remedy • Chapter 6 ITRC IDSS-1, Figure 1 -2

10 After this Training You Should be able to: u Apply the ITRC document to develop an Integrated DNAPL Site Strategy u Understand the advantages of establishing SMART objectives and how to develop SMART objectives u Understand how to monitor technology performance u Effectively consider how to couple and transition treatment technologies u Troubleshoot your remedial approach

11 Chapter 2: Conceptual Site Model (CSM)

12 Status of Your CSM u You might need to update your CSM if …? Source Receptor Plume Receptor

13 Technical Concepts We Will Cover Related to CSM Five topics in compartment model slides

14 u u u Chlorinated Solvent Releases – Chemical Phases and Transport Generalize DNAPL Release and Transport movement and capillary forces vapor Chemical phase distribution Dissolved Plume Interphase Degradation chemical mass Reactions transfer Dissolved plume Sorption, etc. formation & transport Vapor migration (Modified from Parker et al, 2002) ITRC IDSS-1, Figures 2 -1, 2 -3 DNAPL Pore-Scale Distribution Sand Grains DNAPL Water Interphase Chemical Mass Transfer DNAPL Aqueous Vapor Sorbed

15 Mobile DNAPL vs. Residual DNAPL u Mobile DNAPL • Interconnected separate phase that is capable of migrating u Residual DNAPL Soil vapor Dissolved Plume Water • Disconnected blobs and ganglia that are not capable of migrating DNAPL Soil DNAPL Degradation Reactions Sorption, etc. Water (Modified from Parker et al, 2002) ITRC IDSS-1, Figure 2 -2

16 Importance of Geologic Heterogeneity u Tools and concepts commonly applied often underrepresent the actual complexity of DNAPL sites Simplified Geologic Concepts Reality is Complex! ITRC IDSS-1, Figure 2 -4 Intermediate Complexity Models

17 Basic Concept – Contaminant Diffusion u Early time = diffusion into low permeability zones u Late time = diffusion out of low permeability zones “back-diffusion” ITRC IDSS-1, Figure 2 -5 & 2 -6

18 Geologic X-Section: Setting the Stage for a DNAPL Release Key Point: Groundwater flux is dominant in high-permeability zones Groundwater velocity in high-permeability zones >>> average value Groundwater Flow Water Table Medium Permeability High Permeability Zone Low Permeability Zones Highly simplified illustration of heterogeneous geology

Source-Plume Evolution: Early Stage Dominant Early Stage Process: Diffusion from high to low concentration Out of high permeability zone Source Area Groundwater Flow 19 Plume Area Green = Lower Concentration Highly simplified illustration of heterogeneous geology

Source-Plume Evolution: Middle Stage Dominant Middle Stage Process: Relatively uniform contaminant distribution Diffusion at a minimum Source Area Groundwater Flow 20 Plume Area Yellow = Moderate Concentration Low Permeability Zones Highly simplified illustration of heterogeneous geology

Source-Plume Evolution: Late Stage Dominant Late Stage Process: Diffusion out of low permeability zones Mass tied up in low permeability zones Source Area Groundwater Flow 21 Low Permeability Zones Plume Area Green = Lower Concentration Highly simplified illustration of heterogeneous geology

22 Plume Response to In Situ Source Treatment Response is dependent on stage of plume evolution Early Stage u Is contaminant mass accessible to treatment? u In-situ treatment often preferentially treats high permeability zones u “Back-diffusion” controls plume response u Middle Stage Late Stage

23 Plume Response to Source Treatment u u u Mass flux vs. concentration basis Heterogeneous sites – greater plume response Homogeneous sites – lesser plume response Tools – EPA REMChlor (Falta et al, 2007) 1 Plume Flux Reduction u Modified from Basu, et al. (2008) Heterogeneous Sites 0. 8 0. 6 0. 4 Homogeneous Sites 0. 2 0 0 0. 2 0. 4 0. 6 0. 8 1 Source Mass Reduction set 1 -3, variance (ln k)=0. 2 set 2 -3, variance (ln k)=1 set 3 -1, variance (ln k)=3 set 3 -3, variance (ln k)=3

24 14 -Compartment Model u u “Compartment” consists of chemical phase within either the source zone or plume and in either transmissive or low permeability zone Highly conceptualized depiction of potential for contaminant mass flux between compartments Source Zone Phase/Zone Low Perm. Plume Transmissive Low Perm. Vapor DNAPL Aqueous Sorbed ITRC IDSS-1, Table 2 -2 from Sale and Newell, 2011 NA NA

25 14 -Compartment Model u Relative aqueous phase equivalent concentrations u Not mass based Early Stage SOURCE Zone/Phase PLUME Transmissive Low Permeability Vapor LOW DNAPL LOW MODERATE Aqueous LOW MODERATE Sorbed LOW MODERATE Transmissive Low Permeability LOW HIGH MODERATE LOW LOW Middle Stage SOURCE Zone/Phase Low Permeability PLUME Transmissive Low Permeability MODERATE Vapor MODERATE DNAPL MODERATE Aqueous MODERATE Sorbed MODERATE Late Stage SOURCE Zone/Phase PLUME Low Permeability Transmissive Low Permeability Vapor LOW LOW DNAPL LOW Aqueous MODERATE LOW MODERATE Sorbed MODERATE LOW MODERATE ITRC IDSS-1, Table 2 -3 from Sale and Newell, 2011

26 CSM for Soil Gas / Vapor Intrusion Pathway u u u Vapor risk may be driver Key element of CSM Common approach reverse calculate groundwater cleanup target KEY ISSUE - Clear understanding of treatment process and groundwatervapor relationship CAUTION - Equilibrium assumptions vs. nonequilibrium conditions Advection Diffusion Silt Reactions Capillary Fringe Dissolved Contamination Water Table Silt ITRC IDSS-1, Figure 2 -10, Conceptual Model for subsurface vapor pathways (EPA, 2002)

27 CSM Concepts Wrap Up u Do you really understand? • • u Source-plume relationships Transport processes and exposure pathways Stage of source / plume evolution How exposure concentrations will respond to treatment If we don’t understand the problem, we probably can’t solve the problem

28 Chapter 3: Remedial Objectives Remedial objectives Set/revisit Functional Objectives How do you define objectives in a clear and concise manner? u What is the process to make your objectives specific, measureable, attainable, relevant, and time bound? (Doran 2008) u

29 Types of Objectives u Absolute objectives • Based on broad social values § Example: protection of public health and the environment u Functional objectives • Steps taken to achieve absolute objectives § Example: reduce loading to the aquifer by treating, containing, or reducing source

30 Functional Objectives Should be SMART means: u Specific • Objectives should be detailed and well defined u Measureable • Parameters should be specified and quantifiable u Attainable • Realistic within the proposed timeframe and availability of resources u u Relevant • Has value and represents realistic expectations Time-bound • Clearly defined and short enough to ensure accountability

31 Functional Objectives Time Frame u Time frame should accommodate • Accountability • Natural variation of contaminant concentration and aquifer conditions • Reliable predictions • Scientific understanding and technical ability u Team suggests 20 years or less for Functional Objectives Site management and active remediation timeframe may continue much longer

32 Example Site u u u Potential future indoor air vapor risk – PCE in vadose zone and groundwater PCE in groundwater is a potential drinking water risk PCE in soils is a contact and ambient air PROPOSAL– Redevelop the property with no environmental restrictions CLEANUP – 40 µg/kg and 45 µg/kg PCE in soil, 8 µg/L and 5 µg/L PCE in groundwater ITRC IDSS-1, Figure 2 -12

33 Developing a Functional Objective for the Example Site u Absolute Objectives: • Protection of human health and the environment • Redevelop the Mall Area u Generic Functional Objective - Not SMART • Vapor Intrusion Indoor Air Objective – Soils Pathway • Reduce concentrations of volatile organics in the vadose zone that will allow a “No Further Action” for unrestricted use, with no engineering or administrative controls required

34 SMARTify the Functional Objective u SMART Functional Objective • Reduce concentrations of volatile organics in the vadose zone to less than 40 µg/kg within 6 months that will allow a “No Further Action” for unrestricted use, with no engineering or administrative controls required u Meets SMART Criteria • • • Specific – Yes, 40 µg/kg Measureable – Yes, confirmation samples Achievable – Yes, excavation or SVE or ISCO Relevant – Yes, intended use of property Time-bound – Yes, 6 months

35 Questions & Answers u u Conceptual site model Remedial objectives Question and Answer Break u Remedial approach u Monitoring approach u Evaluating your remedy ITRC IDSS-1, Figure 1 -1

36 Chapter 4: Treatment Technologies Chapter 4 Treatment Technologies Evaluate/re- evaluate and select technologies Yes Implement the technology(ies) u u u How do you to avoid the trap of relying on a single remedial technology that won’t do the job? How do you consider site characteristics and site goals when deciding on technologies? How could multiple technology selection and integration help you reach your functional objectives?

37 Four Parts to Section 4 u Remediation technologies and assessing performance (Section 4. 1) u Coupling technologies (Section 4. 2) u Transitioning to other technologies (Section 4. 3) u Example (Section 4. 4)

38 Treatment Technologies u Good summary of key technologies and performance u No discussion of technology niches or sweet spots • Other technology guides are available • No universal consensus by IDSS team u How to fit technologies into 14 -Compartment Model • Need to estimate future performance • Use Orders of Magnitude (Oo. Ms)

39 Table 4. 1: Note the ITRC Publications! Technology Category Physical Removal Chemical/ Biological Containment Example Technologies Example Reference Excavation NAVFAC, 2007 Multiphase Extraction USACE, 1999 Thermal Conductivity/ Electrical Resistance Heating Johnson et. al. , 2009 In Situ Chemical Oxidation ITRC ISCO-2, 2005 In Situ Chemical Reduction Liang et. al. , 2010 In Situ Bioremediation ITRC BIODNAPL-3, 2008 Monitored Natural Attenuation ITRC EACO-1, 2008 Pump and Treat USEPA, 1999 Low-Permeability Barrier Walls NRC, 1997 Permeable Reactive Barriers ITRC PRB-5, 2011 Solidification/Stabilization ITRC IDSS-1, Table 4 -1 USEPA, 2009; ITRC S/S-1, 2011

40 Adding Technologies to the 14 -Compartment Model

41 Order of Magnitude are Powers of 10 Why Use Oo. Ms for Remediation? Hydraulic conductivity is based on Oo. Ms u VOC concentration is based on Oo. Ms u Remediation performance (concentration, mass, Md) can be also evaluated using Oo. Ms…. u • 90% reduction: 1 Oo. M reduction • 99. 9% reduction: 3 Oo. M reduction • 70% reduction: 0. 5 Oo. M reduction (use equation 4. 1. 1) u Example: • Before concentration 50, 000 ug/L • After concentration 5 ug/L • Need 4 Oo. Ms (99. 99% reduction)

42 Where Do You Get Oo. Ms? Option 1: Your experience/knowledge u Option 2: Data from the scientific literature u • Multiple site studies • Recently released ESTCP’s “DNAPL Test” System http: //projects. geosyntec. com/DNAPL/dnapltest. aspx u Option 3: Consult technology specialists / technology vendors

43 Multiple Site Performance Studies u Strong point about these studies… • • • Independent researchers, careful before/after evaluation Repeatable, consistent comparison methodology Describes spectrum of sites Real data, not anecdotal Several studies described in peer reviewed papers:

44 Results from 59 -Site Study Percent reduction in source zone concentration (%) 100 Red Line: 90% Reduction 80 60 Max 75 th % 40 Median 25 th % 20 Min 0 Bioremediation (n=26 sites) Chemical Oxidation (n=23 sites) Thermal Treatment (n=6 sites) Mc. Guire et al. , 2006

45 Others Say Use Caution…. u Not site specific u Some lump pilot scale, full scale u May not account for intentional shutdowns (i. e. they stopped when they got 90% removal) u Don’t account for different levels of design/experience u We are a lot better now….

46 Technology Category 1: Remove Physical Removal u Excavation u Thermal remediation • Reduction in source concentration Detailed study of 14 Sites 1 ≤ 1 Oo. Ms at 9 sites ≥ 2 Oo. Ms at 4 sites 1 Kingston et al, 2010

47 Technology Category 2: React Chemical / Biological u In-situ chemical oxidation • Median 0. 3 Oo. Ms for CVOCs 1 • This and other studies: rebound more prevalent for ISCO than other technologies u In-situ chemical reduction • Deep soil mixing “ZVI Clay” Process: Median 1. 7 Oo. Ms 2 1 Krembs et al. , 2010 2 Olsen and Sale, 2009

48 Technology Category 2: React Chemical / Biological (continued) u Enhanced bioremediation • Median 1. 3 Oo. Ms for Parent 1 • Median 0. 4 Oo. Ms for Total CVOCs u Monitored natural attenuation (MNA) • Median 0. 6 Oo. Ms over average of nine years of MNA at 26 “low-risk” CVOC sites 2 • Sole remedy at 30% of 45 chlorinated MNA sites 3 1 Mc. Guire et al. , 2006 2 Newell et al. , 2006 3 Mc. Guire et al. , 2004

49 Technology Category 3: Contain u Pump and treat u Permeable reactive walls • Zero Valent Iron Walls: Median 0. 8 Oo. Ms TCE from six sites 1 u Low-permeability barriers • 83% of sites met design objectives 2 u Solidification/stabilization 1 Liang et al. , 2010 2 U. S EPA, 1998

50 Technology Coupling (Section 4. 2) u Three types: temporal, spatial, simultaneous u IDSS team experience most common approaches: • Intensive technology followed by passive • Different technology for Source versus Plume • Any technology followed by MNA u In past, “opposing” combinations (ISCO then bio) were thought to be permanent. This has proven to not be the case.

51 Rationale for Coupling Technologies u Contaminant mass, fluxes, concentration, and other factors change over time u Remediation objectives can change as regulations and understanding or risk changes u Multiple contaminants or classes may be present A B

52 Technology Compatibility Matrix u Compatibility matrix of 9 technologies u Examples: • “Generally Compatible” § Thermal followed by In Situ Bio: – Potentially synergistic – Microbes population may be reduced – But then rapid recovery • “Likely Incompatible” § In Situ Reduction followed by In-Situ Oxidation – Destruction of both reagents • “Potentially Compatible but Not An Anticipated Couple” § Bio followed by Surfactant Flushing – Would probably work, but unlikely to be coupled ITRC IDSS-1, Table 4 -2

53 Transitioning Between Technologies (Section 4. 3) Potential Transition Triggers: u Contaminants concentrations • Most likely to be contacted by the public or environment • Concentrations in a single key phase u Contaminant phase (particularly free phase) u Contaminant lineage, parent vs. daughters u Site conditions created during method execution u Cost per unit of contaminant destroyed

54 Remedy Transition Steps (Figure 4 -1) 1. 2. 3. 4. Remedy implementation Process and performance monitoring Data evaluation Are we making progress? Yes 5. Continue remedy No 6. Should we optimize? Yes 7. Optimization No 8. Transition to next remedy

55 An Example to Pull It All Together (Section 4. 4) We want to couple: u 14 -Compartment Model u Oo. Ms u Remedy Performance To answer the question: u Will I reach my objectives?

56 Source Area Excavation Source Low Permeability Transmissive Before Tech. Perf After Vapor 2 3 0 3 3 0 DNAPL 0 3 0 Aqueous 1 3 0 2 3 0 Sorbed 3 3 0 ZONE / PHASE Key Equivalent aqueous conc. ~1000 µg/l Equivalent aqueous conc. ~10 µg/l Equivalent aqueous conc. ~1 µg/l ITRC IDSS-1, Figure 4 -2

57 Section 4 Summary u Three important concepts (Section 4. 1) • Remediation is an Order of Magnitude (Oo. M) affair • Oo. Ms go into 14 -Compartment Model • Get Oo. Ms from your experience, multiple site studies, or technology experts u Coupling technologies (Section 4. 2) • Examples: Active-then-passive; Source-vs. -plume • Use the Compatibility Matrix (Figure 4 -2) u Transitioning (Section 4. 3) • IDSS flowchart (Figure 4 -1) can help

58 Chapter 5 Monitoring Has a more efficient alternative become available? No Monitor performance For each treatment area Chapter 5: Monitoring How do you design a monitoring program that assesses your progress towards reaching your functional objectives? u What data should you collect to evaluate remedy performance? u

59 Type of Monitoring u Performance Monitoring • At end of the day, did it work? • Compare to SMART functional objectives u Process Monitoring • We turned it on – is it working correctly? • Data used to optimize system u Compliance Monitoring • How are we compared to regulatory limits? • Is everyone safe? Point of Compliance Well

60 Media to Monitor DNAPL (if present) u Aquifer matrix solids u Soil gas u Groundwater u Surface water u

61 Metrics u Concentration mg/L, mg/kg, ppmv u Mass of contaminants: Kilograms u Mass Flux Mass Discharge Grams per m 2 per day Grams per day

62 Data Evaluation u Key concept: Maintaining and Improving the Conceptual Site Model • Visualization tools can help • Stats help you understand trends City Supply Well Source Area Plume

63 Data Evaluation – Trends u Trends • • u Remediated Not remediated Possible interpretations Types of decisions needed Example statistical tools • MAROS § Free download: www. gsi-net. com • Summit monitoring tools • GTS algorithm ITRC IDSS-1, Figure 5 -1 Decision Framework

64 Modeling for Performance Monitoring u Source zone models • Simulates impact of remediation or MNA on source u Fate and transport models • Evaluates plume stability u Example: • REMChlor – Search “REMChlor EPA” • NAS – Search “Natural Attenuation Software”

65 Example REMChlor Output (R. Falta, CSGSS “Practical Tools” Short Course)

66 Optimizing Monitoring u Monitoring network • Any redundant wells or data gap area? u Frequency and duration • Do I need to sample quarterly? Lots of research. u Contaminant and constituent • Can 1 or 2 compounds explain the big picture? u Key tools: • MAROS and GTS

67 Field data, lab data and literature Data Analysis Tools {hand calculations + …} Screening Tools {experience + …} remedial options / Scenarios performance parameters conceptual model Source. DK, Mass Flux Toolkit, … MAROS, GTS … source mass, geometry, and discharge groundwater concentrations and trends, flow rates, etc. Technically based information to support a decision 67

68 Chapter 6: Remedy Evaluation How do you create a plan to evaluate, optimize, and revise your remedial strategy? Chapter 6 u Re- evaluate the basis of your original decisions beginning with the CSM Yes Remedy evaluation Is progress toward the Functional Objectives acceptable? No Are Functional Objectives met? No Yes Closure Strategy ITRC IDSS-1, Figure 1 -2 excerpt Evaluate progress

69 Key Questions to Consider Are Functional Objectives being met – is progress acceptable? u Can you be more efficient? u How do you troubleshoot if you are not? u ITRC IDSS-1, Figure 1 -2 excerpt

70 Are Objectives Being Met? u Periodic evaluation • Timing is everything • Often evaluation is measuring progress towards the endpoint • Plan for contingency u Identify changes that have occurred, remaining potential risks, and opportunities for improvement (i. e. optimization) ITRC IDSS-1, Figure 1 -2 excerpt

71 Remedy Optimization u Advances in long-term site management due to 1. Dynamic nature of environmental law 2. Improved technology 3. Improved understanding of impacts of remedial actions u u ITRC IDSS-1, Figure 1 - excerpt Why optimize? • Enhanced operation of remedy • Cost reduction • Change in resource use Technology optimization • New/better practices • Technology advancement • Transition technology

72 Troubleshooting: Revisit CSM Purpose of CSM (EPA 2008): u Organize project information. u Obtain consensus about sources of uncertainty u Identify uncertainty that hampers decisionmaking u Identify additional data needed to reduce uncertainties or to test assumptions u Establish basis for • Decisions about risk/ remediation/ reuse • Decisions regarding remedial cost- ITRC IDSS-1, Figure 1 -2 excerpt effectiveness and efficiency • Identifying decision units (i. e. , area/volume, or objects treated as a unit)

73 Troubleshooting: Revisit CSM u Common inaccuracies Groundwater Flow • • 3 D delineation Boundary conditions Surface features Multiple / alternate source Source Area • • • Age and nature of release Heterogeneity Diffusion Seasonal changes Preferential pathways Vapor phase transport Plume Area Source treatment Low Permeability Zones Green = Lower Concentration

74 Troubleshooting: Revisit Objectives ITRC IDSS-1, Figure 1 -2 excerpt Reasons objectives don’t work: u Metrics not aligned with objectives u Unrealistic expectations of technology performance u Data does not support objectives u Regulatory goals not achievable in predicted time u Lack of interim objectives u NEED TO BE SMART

75 Troubleshooting: Technology u Technology performance evaluation • Expected versus actual performance u Technology performance expectations • Appropriate technologies based on the revised site understanding and the actual performance of technologies already employed u ITRC IDSS-1, Figure 1 -2 excerpt Technology cessation/ addition/transition – • Re-evaluate the technology(ies) in use to other applicable technologies

76 Technology Decisions u Continue Source treatment with existing technology u Optimize existing technology u Cease operation u Transition to another approach

77 Example: Remedial Decision Making % of Baseline Mass Discharge Overall Objective: Decrease mass discharge from source zone by 99% in 5 years 100 Aggressive treatment: Reduce mass discharge by 90% in 5 months Natural Attenuation: Additional 9% reduction in 4. 5 years 10 1 0 500 1000 Days from start of treatment Expected 1500 2000

78 Actual vs. Predicted Performance Actual reduction 60% instead of 90% % of Baseline Mass Discharge 100 10 • Should aggressive treatment continue? • What is the impact towards achieving the overall objective of a 99% reduction in mass discharge? 1 0 20 40 60 80 100 120 Days from treatment Expected Performance Actual Performance 140

Impact of Reduced Treatment Efficiency and Decision Making % of Baseline Mass Discharge 79 • Is revised timeframe OK? • Yes: shut down aggressive treatment • No: • Troubleshoot /operate aggressive treatment longer • Transition to another technology 100 10 Add 2 years to achieve goal 1 0 500 1000 1500 2000 2500 3000 Days from treatment Aggressive Expected Aggressive Actual MNA Expected MNA Actual

80 Remedy Evaluation Summary CSM is a living document u Functional objectives must be SMART u Plan transitions to other technologies u Repeated performance evaluation u Reevaluate your Strategy (IDSS) u

81 Course Summary Maintain and improve conceptual site model u SMART functional objectives u Multiple technologies u Iterative performance evaluation u Reevaluate your strategy u Regulatory issues u An IDSS creates an accurate, comprehensive management model for sites where chlorinated solvent occurs in multiple phases and is remediated using several methods over an extended period of time and under conditions of uncertainty and change

82 ITRC DNAPL and Related Products Technical and Regulatory Guidance: Integrated DNAPL Site Strategy (IDSS-1, 2011) Use and Measurement of Mass Flux and Mass Discharge (Mass. Flux-1, 2010) Technical and Regulatory Guidance; ISB of Chlorinated Ethenes, DNAPL Source Zones (BIODNAPL-3, 2008) In Situ Bioremediation of Chlorinated Ethene DNAPL Source Zones: Case Studies (BIODNAPL-2, April 2007) Overview of In Situ Bioremediation of Chlorinated Ethene DNAPL Source Zones (BIODNAPL-1, October 2005) Strategies for Monitoring the Performance of DNAPL Source Zone Remedies (DNAPLs-5, August 2004) An Introduction to Characterizing Sites Contaminated with DNAPLs (DNAPLs-4, September 2003) Technical and Regulatory Guidance for Surfactant/ Cosolvent Flushing of DNAPL Source Zones (DNAPLs-3, April 2003) DNAPL Source Reduction: Facing the Challenge (DNAPLs-2, April 2002) Dense Non-Aqueous Phase Liquids (DNAPLs): Review of Emerging Characterization and Remediation Technologies (DNAPLs-1, June 2000)

83 Thank You for Participating u Question and answer break u Links to additional resources • http: //www. clu-in. org/conf/itrc/IDSS/resource. cfm u Feedback form – please complete • http: //www. clu-in. org/conf/itrc/IDSS/feedback. cfm Need confirmation of your participation today? Fill out the feedback form and check box for confirmation email.